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added section for aerobes and facultative anaerobes that can produce IVA
Isovaleric acid can also be produced by the oxidation of hops <ref>[http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1970.tb03256.x/pdf Green, C. P. The Volatile Water-Soluble Fraction Of Hop Oil. Aug 24, 1909.]</ref><ref>[https://books.google.com/books?id=oWQdjnVo2B0C&pg=PA498&lpg=PA498&dq=oxidation+of+hop+resins+3-Methylbutanoic+acid&source=bl&ots=wmM8jX-qJY&sig=_wFzzuUA40eg0vMNc-7vfU6tneA&hl=en&sa=X&ei=XX2PVJHDI4bcoATjoYK4BA&ved=0CEcQ6AEwBQ#v=onepage&q=oxidation%20of%20hop%20resins%203-Methylbutanoic%20acid&f=false Oliver, Garret. The Oxford Companion to Beer. 2001. Pg 498.]</ref>.
==Other Producers==
Other bacteria have been shown to create isovaleric acid, and may contribute to the production of it in beer in unsanitary conditions. ''Bacillus amyloliquefaciens'' and ''B. atrophaeus'' are Gram-positive, aerobic bacteria and have been shown to produce isovaleric acid <ref name="Vasquez">[http://bashanfoundation.com/gmaweb/pdfs/vazquez1.pdf Phosphate-solubilizing microorganisms associated with the rhizosphere of mangroves in a semiarid coastal lagoon. P. Vazquez, G. Holguin, M.E. Puente, A. Lopez-Cortes, Y. Bashan. 2000.]</ref><ref>[http://web.mst.edu/~microbio/BIO221_1998/B_amylo.html Bacillus amyloliquifaciens. Carl Sather's website. Retrieved 10/06/2015.]</ref><ref>[http://www.researchgate.net/publication/263432119_Bacillus_atrophaeus_main_characteristics_and_biotechnological_applications__a_review Bacillus atrophaeus: main characteristics and biotechnological applications – a review. Sandra R B R Sella, Luciana Vandenberghe, Carlos Ricardo Soccol. 2014.]</ref>. ''Xanthobacter agilis'' is a Gram-negative aerobic bacteria that can produce isovaleric acid <ref name="Vasquez"></ref><ref>[http://www.thelabrat.com/restriction/sources/Xanthobacteragilis.shtml Xanthobacter agilis. The Lab Rat. Retrieved 10/06/2015.]</ref>. ''Paenibacillus macerans'' is a facultative anaerobe (can utilize oxygen if present, but oxygen is not required) that can produce isovaleric acid. ''P. macerans'' is a Gram-variable bacteria, meaning that it can produce Gram-positive and Gram-negative rods <ref>[https://en.wikipedia.org/wiki/Paenibacillus_macerans Paenibacillus macerans. Wikipedia. Retrieved 10/06/2015.]</ref>.
==Metabolic Breakdown==